1. Field of the Invention
The present invention relates to an LED illumination lamp device for use as an illumination lamp for general lighting, a headlight for vehicle, or the like.
2. Description of Related Art
An LED illumination lamp device using a light emitting diode element (hereinafter, referred to as LED element) has the advantageous effects of a lower heat release value, a longer operating life, and so on, in comparison with a conventional illumination lamp without using LED elements such as an electric light bulb. In recent years, LED illumination lamps have been widely used in various circles as illumination lamps for general lighting, headlights for vehicle, or the like. Because one LED element emits only a small volume of light, it has become conventional practice to install a large number of LED elements in one illumination lamp to ensure emission of a large volume of light.
A known example of an LED illumination lamp is the bulb-type LED illumination lamp in which a large number of LED elements are disposed on a side surface of a cylindrical supporting member to form an electric light bulb (for reference, see Japanese Patent Laid-Open No. 2004-296245, FIG. 1, paragraphs 0014 to 0021, Japanese Patent Laid-Open No. 2004-296249, FIG. 1, paragraphs 0012 to 0019, and Japanese Patent Laid-Open No. 2004-342574, FIGS. 1 to 3, paragraphs 0009 to 0014, and so on).
However, when installing a large number of LED elements in the above-mentioned conventional bulb-type LED illumination lamp, it has been necessary to increase either the diameter or length of the cylindrical supporting member. Therefore, the conventional bulb-type LED illumination lamp has been limited in its ability to assure bright illumination while maintaining a compact size.